JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://arshaw.com/js/fullcalendar/fullcalendar.css">
<script src="http://arshaw.com/js/fullcalendar/fullcalendar.min.js"></script>
<script src="http://arshaw.com/js/fullcalendar/gcal.js"></script>
<span>Feed url: </span>
<input id="feed" value="http://www.google.com/calendar/feeds/en.usa%23holiday@group.v.calendar.google.com/public/basic"/>
<input id="Clicker" type="button" value="Load Data" />
<div id="cal"></div>

JavaScript

$('#cal').fullCalendar({
    //Options: I don't have any
});

$('#Clicker').click(function(){
    $('#cal').fullCalendar('addEventSource', $.fullCalendar.gcalFeed($('#feed').val()));
});